1641 - Effect of zoledronic acid used concurrently with radiation therapy on growth of bone epiphysesal plaque

Date 28 September 2012
Event ESMO Congress 2012
Session Publication Only
Topics Supportive Care
Presenter Oznur Yuksel
Authors O. Yuksel1, C. Parlak2, O.C. Guler1, C. Onal1, O. Ozyilkan3, E. Topkan1
  • 1Department Of Radiation Oncology, Baskent University Adana Medical Faculty, 01120 - Adana/TR
  • 2Baskent University Adana Medical Faculty, 01120 - Adana/TR
  • 3Medical Oncology, Baskent University Faculty of MedicineAdana Uygulama Ve Arastirma Mer., TR-01120 - Adana/TR

Abstract

Background

Radiotherapy (RT) has an important and efficient role in the treatment of majority of childhood cancers. However, shape deformities and shortness may result from the delivery of RT in children with incomplete skeletal growth. Fractionation studies and trials using amiphostine and melatonin as radioprotectant have demonstrated significant reduction in such RT-induced deformities. In this study, impact of zoledronic acid (ZA), a commonly used drug in oncological practice, on prevention of RT-induced epiphyseal injury was investigated.

Materials and methods

Six week old male Sprague-Dawley rats were enrolled to one of the four groups (n = 7 for each): Group 1 was assigned as control group; Group 2 received fractionated RT alone; Group 3 received 20 µ/kg ZA injection alone; and Group 4 received 20 µ/kg ZA injection prior to fractionated RT. Fractionated RT in the irradiated groups was delivered to distal femur and proximal tibia in the left legs of each rats to a total dose of 24 Gy in 3 fractions with the contralateral right leg as the non-irradiated control. ZA injection in Group 3 was performed on the day before the RT. Bone growth was calculated according to the lengths of femur, tibia and total leg measured on the radiographs taken at the time and 6 weeks after the delivery of RT.

Results

RT resulted in a mean percent overall limb growth loss of 56.2 ± 6.7 and a mean percent overall limb discrepancy of 12.7 ± 1.3. Administration of 20 µ/kg ZA before RT reduced the mean percent overall limb growth loss and the mean percent overall limb discrepancy to 35,4 ± 6,8 and 9,2 ± 1,8, respectively. These values were significantly different compared with the groups receiving irradiation alone (P = 0.001 for each).

Conclusion

These results demonstrate the potential for ZA administered before fractionated RT to significantly reduce the RT-induced epiphyseal injury, with no additional toxicity.

Disclosure

All authors have declared no conflicts of interest.